The invention discloses a method for manufacturing a surface crack defect test block for nondestructive flaw detection. By using the mechanism of production of surface cracks in the process of welding, the invention provides a method for quickly manufacturing the surface crack defect test block. The method manufactures a commonly used surface weld crack test block through the approaches of addingsulfur elements into a welding seam, reasonably controlling a welding process and the like. The surface cracks manufactured by the method are different from artificial defects of a commonly used flawdetection standard test block, the crack defects are real and practicable, can be applied to nondestructive flaw detection methods of ultrasonic flaw detection, penetrant flaw detection and the like,and are significant for training and evaluation of license changing and obtaining of nondestructive flaw detection personnel, and improving perceptual and rational knowledge of surface crack defect flaw detection signals of the nondestructive flaw detection personnel.